Dark Jellyfish

Sci-fi horror movie from the early 1980s?

Featured flying glow-in-the-dark jellyfish type creatures that landed on people and sucked their blood dry. I assume they were aliens. All I remember is that they were fluorescent green and landed with a splat. Not "Slither", but somewhat similar in premise. Does anyone recall the name of this film?
They weren't actual jellyfish. They flew, like little throbbing flying saucers. The movie did not take place underwater.
I think they may have been more like sand dollars than jellyfish, now that you mention it. Regardless, it's gotta be the same movie.

Was that the one with Charlie Sheen, I think the movie is The Arrival?